RULERS OF THE ANCIENT SEAS 47 



And now, as the wheels of time and change rolled 

 slowly on, sharks again came uppermost, and the 

 warmer Eocene and Miocene oceans appear to have 

 fairly teemed with these sea wolves. There were small 

 sharks with slender teeth for catching little fishes, there 

 were larger sharks with saw-like teeth for cutting slices 

 out of larger fishes, and there were sharks that might 

 almost have swallowed the biggest fish of to-day whole, 

 sharks of a size the waters had never before contained, 

 and fortunately do not contain now. We know these mon- 

 sters mostly by their teeth, for their skeletons were 

 cartilaginous, and this absence of their remains is prob- 

 ably the reason why these creatures are passed by while 

 the adjectives huge, immense, enormous are lavished on 

 the Mosasaurs and Plesiosaurs — animals that the great- 

 toothed shark, Carcharodon megalodon, might well have 

 eaten at a meal. For the gaping jaws of one of these 

 sharks, with its hundreds of gleaming teeth must, at a 

 moderate estimate, have measured not less than six 

 feet across. 



The great White Shark, the man-eater, so often found 

 in story books, so rarely met with in real life, attains a 

 length of thirty feet, and a man just makes him a good, 

 satisfactory lunch. Now a tooth of this shark is an inch 

 and a quarter long, while a tooth of the huge Megalodon 

 is commonly three, often four, and not infrequently five 

 inches long. Applying the rule of three to such a tooth 

 as this would give a shark 120 feet long, bigger than 

 any whale, to whom a man would be but a mouth- 

 ful, just enough to whet his sharkship's appetite. Even 

 granting that the rule of three unduly magnifies the 

 dimensions of the brute, and making an ample reduction, 

 there would stiU remain a fish between seventy-five and 

 one hundred feet long, quite large enough to satisfy 

 the most ambitious of tuna fishers, and to have made 



